Lifelong decrements in neurocognitive function (NF) are among the most prominent concerns for childhood cancer survivors, which can result in psychosocial problems of survivors and extend to the entire family. Routine assessment is especially critical for survivors as NF deficits may first appear years after the treatment. Current NF assessment relies on neuropsychological test battery, which is lengthy, expensive, and produces practice effects if it is administered routinely. Given these obstacles, there is a need for a measurement system that can provide brief and precise assessments tailored to the individual, thereby making it possible to screen patients who need comprehensive neuropsychological testing in busy clinical settings. To address this need, we propose to develop a comprehensive perceived cognitive function item bank (PCF) for children 7-21 years of age, which facilitates the development of individualized computerized adaptive testing (CAT) and short-forms that can serve as the screening tool. This bank would augment an existing adult PCF bank thereby providing the basis for psychometrically sound assessment across the disease continuum and life span. We propose the development of a parent proxy version for children of all ages and a self-reported version for children ages 1.3-21. The development of the pedsPCF bank will be accomplished through the successful completion of the following three aims. Aim 1 is to generate a perceived cognitive function item pool for the pediatric population. We will develop this pool by reviewing items from the existing adultPCF bank, an item library that we have built within the scope of two federally funded projects, and current literature. Items will be rigorously reviewed by clinicians, children and parents for their content validity. New items will be added to reflect developmental differences as necessary to ensure the comprehensiveness of the pool. Aim 2 is to examine the psychometric properties of the pedsPCF item bank(s) via the completion of two sub-aims: a) evaluate the essential unidimensionality of the pedsPCF bank;and b) calibrate the item bank(s) using item response theory (IRT) models. Aim 3 is to examine the clinical usefulness of the pedsPCF item bank(s) in relation to external clinical criteria. This includes: a) using discriminant function analysis and receiver operating characteristic curve approaches to establish cut scores;b) using IRT to develop user-friendly short-forms in screening patients for comprehensive testing;and c) using both anchored and distribution based approaches to identify minimally important differences in PCF. With the completion of this project, we hope to reach our ultimate goal of developing a measurement system that 1) can monitor patient perceived cognitive function throughout developmental stages, 2) can serve as the foundation for CAT and short-forms, which can then serve as a clinically meaningful screening tool.